1. Field of the Invention
This invention relates to an x-ray technique-based nonintrusive inspection apparatus. An x-ray technique-based nonintrusive inspection apparatus according to the invention may, for example, be used for nonintrusively inspecting closed containers before being loaded into a loading bay of an aircraft, or may include technologies which may find application in other similar or different inspection apparatus.
2. Discussion of Related Art
Inspection apparatus are commonly used for nonintrusively inspecting luggage and other dosed containers before being loaded into a loading bay of an aircraft. Older generation inspection apparatus relied merely on conventional x-ray technology for nonintrusively inspecting closed containers. More recently, inspection apparatus which rely on computer tomography (CT) scanning technology have also been utilized. An inspection apparatus utilizing CT scanning technology is described in U.S. Pat. Nos. 5,182,764 and 5,367,552 by Peschmann et al. which are assigned to the assignee of the present case and which are hereby incorporated by reference.
The invention provides an x-ray technique-based nonintrusive inspection apparatus which allows for xe2x80x9cradiation lockingxe2x80x9d as will be described in more detail in the description that follows. The inspection apparatus includes loading inspection and unloading tunnel sections, first, second and third conveyor apparatus, an x-ray source, first, second, third and fourth actuation devices, and first, second, third and fourth radiation resistant closure members.
Each tunnel section has a respective first end and a respective second end opposing the first end thereof. The inspection tunnel section is located in line after the loading tunnel section so that the second end of the loading tunnel section is adjacent the first end of the inspection tunnel section. The unloading tunnel section is located in line after the inspection tunnel section so that the second end of the inspection tunnel section is located adjacent the first end of the unloading tunnel section.
The first conveyor apparatus has at least one conveyor belt which is at least partially located within the loading tunnel section and which, upon movement, is capable of moving an object from the first end of the loading tunnel section to the second end of the loading tunnel section. The second conveyor apparatus has at least one conveyor belt which is at least partially located within the inspection tunnel section and which, upon movement, is capable of moving an object from the first end of the inspection tunnel section to the second end of the inspection tunnel section. The third conveyor apparatus has at least one conveyor belt which is at least partially located within the unloading tunnel section and which, upon movement, is capable of moving an object from the first end of the unloading tunnel section to the second end of the unloading tunnel section.
The x-ray source, when operated, creates radiation within the inspection tunnel section.
The first closure member is movable by the first actuation device between an open position wherein the first end of the loading tunnel section is open, and a closed position wherein the first closure member closes the first end of the loading tunnel section. The second closure member is movable by the second actuation device between an open position wherein the second end of the loading tunnel section is in communication with the first end of the inspection tunnel section to allow for movement of an object from the loading tunnel section to the inspection tunnel section, and a closed position wherein the second closure member substantially closes off communication between the first and inspection tunnel sections. The third closure member is movable by the third actuation device between an open position wherein the second end of the inspection tunnel section is in communication with the first end of the unloading tunnel section to allow for movement of an object from the inspection tunnel section to the unloading tunnel section, and a dosed position wherein the third closure member substantially closes off communication between the second and unloading tunnel sections. The fourth closure member is movable by the fourth actuation device between an open position wherein the second end of the loading tunnel section is open, and a closed position wherein the fourth closure member doses the second end of the unloading tunnel section.
The inspection apparatus may further include first, second, third and fourth curtain rollers, each being rotatable by a respective one of the actuation devices. The closure members may be curtains and each curtain may be secured to a respective curtain roller so as to be rolled onto or from the curtain roller upon rotation of the curtain roller.
The inspection apparatus may further include a controller which controls power supplied to the respective actuation devices. The controller may be programmed to synchronize the actuation devices so that, at least when the x-ray source creates radiation within the inspection tunnel section, at least one of the first and second closure members is in its respective closed position and at least one of the third and fourth closure members is in its respective dosed position. The controller may turn the radiation source off when both the first and second closure members are not entirely in their respective dosed positions, or when both the third and fourth closure members are not entirely in their respective dosed positions.
The invention also provides a method of nonintrusively inspecting an object in a xe2x80x9cradiation lockingxe2x80x9d manner, utilizing an x-ray technique-based nonintrusive inspection apparatus, that permits x-rays generated in an inspection tunnel section thereof to remain on continuously. A first radiation resistant closure member is moved into an open position wherein a first end of a loading tunnel section is open, while a second radiation resistant closure member is in a closed position wherein it doses a second end of the loading tunnel section opposing the first end of the loading tunnel section. An object is moved through the first end of the loading tunnel section into the loading tunnel section while the second closure member remains in its closed position. The first closure member is then moved into a closed position wherein the first closure member closes the first end of the first tunnel. After movement of the first closure member into its closed position, the second closure member is moved into an open position wherein the second end of the loading tunnel section is in communication with a first end of a inspection tunnel section. The object is then moved from the loading tunnel section into the inspection tunnel section. After movement of the object into the inspection tunnel section, the second closure member is moved into its closed position so as to substantially dose off communication between the first and inspection tunnel sections. The object is then radiated within the inspection tunnel section.
The confines of the inspection tunnel section may be radiated while the object is moved into the loading tunnel section.
The first closure member may remain in its closed position while the object is moved into the inspection tunnel section. The confines of the inspection tunnel section may be radiated while the object is moved into the inspection tunnel section.
The invention also provides a method of nonintrusively inspecting an object by simultaneously utilizing an x-ray line scanner subsystem and a CT scanner subsystem, in an x-ray technique-based nonintrusive inspection apparatus, which may be in a dose relationship relative to one another. A front portion of the object is first scanned utilizing the x-ray line scanner subsystem. A section within the front portion of the object is scanned utilizing a CT scanner subsystem. A rear portion of the object is then scanned, utilizing the x-ray line scanner subsystem, after the section in the front portion is scanned utilizing the CT scanner subsystem.
The object may, for example, be a dosed container which is nonintrusively inspected.
The object may be scanned while being moved relative to the x-ray line scanner subsystem and the CT scanner subsystem, and the front portion and the rear portion may be scanned without altering the direction of movement of the object relative to the x-ray line scanner subsystem and the CT scanner subsystem, although it may be necessary to bring the object to a halt relative to the CT scanner subsystem. Movement of the object relative to the x-ray line scanner subsystem and the CT scanner subsystem may be progressively reduced after the section is scanned by the x-ray line scanner subsystem but before the section is scanned by the CT scanner subsystem.
The invention also provides an x-ray technique-based nonintrusive inspection apparatus having both x-ray and CT scanning capabilities within a single tunnel section. The inspection apparatus includes at least one tunnel section, a conveyor apparatus, an x-ray line scanner subsystem, and a CT scanner subsystem. The tunnel section has first and second opposed ends. The conveyor apparatus has at least one conveyor belt which is at least partially located within the tunnel section. The conveyor belt, upon movement, is capable of transporting an object from the first end to the second end of the tunnel section. The x-ray line scanner subsystem is positioned to scan at a first plane within the tunnel section. The CT scanner subsystem is positioned to scan at a second plane within the tunnel section.
The first and second planes may be located by distance of less than 110 centimeters from one another.
Preferably, the same conveyor belt conveys the object from the first plane to the second plane.
The inspection apparatus may further include a base frame, and a support structure having a lower end secured to the base frame and extending upwardly therefrom, and the x-ray line scanner subsystem and the CT scanner subsystem may both the mounted to the support structure.
The invention also provides an x-ray technique-based nonintrusive inspection apparatus having good structural integrity. The inspection apparatus includes a base frame of monocoque design, a support structure, and a CT scanner subsystem. The support structure is secured to the base frame. The CT scanner subsystem is rotatably mounted to the support structure. Although having specific application for x-ray technique-based nonintrusive inspection apparatus used for detecting contraband in closed containers, inspection apparatus are also envisioned having base frames of monocoque design which are not necessarily used for the detection of contraband within closed containers.
A motor may be coupled to the CT scanner subsystem so as to rotate the CT scanner subsystem, for example at a rate of at least 100 revolutions per minute.
The CT scanner subsystem may define an opening having a cross-dimension of at least 110 centimeters.
The CT scanner subsystem may define an opening and the inspection apparatus may further include a conveyor apparatus mounted to the base frame. The conveyor apparatus may have a conveyor belt which passes through the opening. The conveyor belt may have a width of at least 90 cm.
The CT scanner subsystem may include a gantry enclosure, a radiation source mounted on one side to the gantry enclosure so that, when the radiation source is operated, the confines of the gantry enclosure are radiated, the gantry enclosure being at least partially made of lead.
The invention also provides a CT scanner subsystem of a nonintrusive inspection system which is at least partially self shielded so as to attenuate leaking of radiation therefrom to acceptable levels. The CT scanner subsystem may include first and second spaced gantry plates, at least one spacer, a ring, and an x-ray source. The first and second gantry plates each have a respective gantry aperture formed therein. The at least one spacer is located between the gantry plates so that the at least one spacer together with the gantry plates define a partial gantry enclosure. The ring is located on the gantry enclosure and allows the gantry enclosure to be mounted to a support structure for rotation about an axis through the gantry apertures. The x-ray source is secured to the gantry enclosure at one side thereof so that, when the x-ray source is operated, the confines of the gantry enclosure are at least partially radiated. The gantry enclosure is at least partially made of a material which substantially attenuates radiation leakage from the gantry enclosure i.e. by a degree which is much more than for example attenuation of radiation with steel. The gantry enclosure may for example include a liner of lead or another material which, substantially attenuates radiation leakage on the first or second gantry plates or on the spacer. The x-ray source may include an x-ray tube and a liner, of lead or another material which substantially attenuates radiation leakage, on the x-ray tube.
The invention also provides an x-ray technique-based noninstrusive inspection apparatus including a support frame, a CT scanner subsystem, and a tunnel portion. The CT scanner subsystem may include first and second spaced gantry plates, at least one spacer, and an x-ray source. Each gantry plate may have a respective gantry aperture formed therein. The at least one spacer may be located between the gantry plates so that the at least one spacer together with the gantry plates define a partial gantry enclosure. The x-ray source may be secured to the gantry enclosure at one side thereof so that, when the x-ray source is operated, the confines of the gantry enclosure are at least partially radiated. The gantry enclosure is at least partially made of a material which substantially attenuates radiation leakage from the gantry enclosure. The CT scanner subsystem is mounted to the support frame for rotation about an axis through the first and second gantry apertures. The tunnel portion is nonrotatably mounted to the support frame and has an end which mates with the gantry aperture in the first gantry plate. The tunnel portion is also at least partially made of a material which substantially attenuates radiation leakage from the tunnel portion.
The invention also provides an x-ray technique-based noninstrusive inspection apparatus which is easily maintainable because of the location of a flexible member such as a belt or a chain which is used for driving a CT scanner subsystem of the inspection apparatus. The inspection apparatus includes a support frame, a CT scanner subsystem, at least first, second and third pulleys, and a flexible member. The CT scanner subsystem is rotatably mounted to the support frame and has a circular outer surface. The first, second and third pulleys are mounted around the CT scanner subsystem to the support frame. The flexible member runs over the first, second and third pulleys. A first section of the flexible member runs from the first pulley to the second pulley in a first direction around and over the circular outer surface. A second section of the flexible member returns from the second pulley over the third pulley back to the first pulley in a second direction, opposite to the first direction, around the circular outer surface.
According to one aspect of the invention, an x-ray technique-based nonintrusive inspection apparatus is provided including at least a first tunnel section, an x-ray source, at least a first actuation device, and at least a first radiation resistant closure member. The first tunnel section has first and second opposed ends. The x-ray source, when operated, creates radiation within the first tunnel section. The first radiation resistant closure member is movable by the actuation device between an open position wherein the first end of the first tunnel section is open, and a closed position wherein the first closure member doses the first end of the first tunnel section. The inspection apparatus thus has an xe2x80x9cactivexe2x80x9d closure member. Specific advantages of active closure members are discussed in the description that follows.
The inspection apparatus may include a tensioning roller which is rotatably mounted to the support frame. The tensioning roller acts on the curtain and tends to roll the curtain from the curtain roller.
The inspection apparatus may further include a spring which is biased between the support frame and the tensioning roller so as to tend to rotate the tensioning roller.
The inspection apparatus may further include a sheet which has a first portion attached to the curtain roller and a second portion attached to the tensioning roller, so as to connect the tensioning roller to the curtain. The sheet may be secured to the curtain roller without intervention by the curtain.
The curtain preferably hangs from one side of the curtain roller and the tensioning roller is preferably located on the same side of the curtain roller as the side of the curtain roller from which the curtain hangs.
The invention also provides an effective manner of making a collimator for a detector array of the x-ray detection apparatus. First, a die is injected with a material. The material is then allowed to set within the die to form a body. The body is then removed from the die. The body typically includes a support structure and a plurality of septa secured to the support structure.
The material preferably includes a first, lead component comprising at least 90 percent thereof. The material may include a second component which is stronger than lead. The second component may, for example, include tin.
According to the method, a collimator for a detector array may be formed wherein septa of the collimator converge. The collimator may include a body which includes a support structure and a plurality of septa secured to the support structure. Center lines of two of the septa located next to one another converge in a first direction so that the septa may be aligned with a radiation source, but surfaces of the two septa facing one another do not converge in the first direction so as to allow for removal of the body from a die which is used to form the body.
The invention also provides a collimator for a detector array of an x-ray inspection apparatus, which includes a body which includes at least one support structure and a plurality of septa secured to the support structure. The body is made of a material having a first, lead component comprising at least 90 percent thereof.
For added strength, the body may include first and second support structures with the septa secured between the first and second support structures.
The invention also provides a collimator for a detector array of an x-ray inspection apparatus which allows for modular design of detector arrays. The collimator includes a body having a plurality of registration formations thereon. The body includes a support structure and a plurality of septa secured to the support structure.
Each registration formation may be a respective notch in a portion of the body.
The invention also provides an x-ray technique-based nonintrusive inspection apparatus which allows for easy release of parts of containers which become jammed between rollers of conveyor apparatus which are located sequentially one after the other. The inspection apparatus includes a base frame, a tunnel section, a conveyor belt mounting structure, front and rear conveyor rollers, and a conveyor belt. The tunnel section has a first end and a second end opposing the first end, and is mounted to the base frame. The front and rear rollers are rotatably mounted to the conveyor belt mounting structure. The conveyor belt runs over the front and rear conveyor rollers. The conveyor belt mounting structure is mounted to the base frame for at least limited movement, between first and second positions, in a direction in which the conveyor belt moves between the front and rear conveyor rollers. The conveyor belt extends at least some distance between the first and second ends through the tunnel section.
The invention also extends to a method of assembling an x-ray technique-based nonintrusive inspection apparatus wherein a conveyor belt of the inspection apparatus is preinstalled and wherein the conveyor belt may be pre-tensioned. A conveyor belt mounting structure, having front and rear conveyor rollers rotatably mounted thereto, and a conveyor belt over the front and rear conveyor rollers, is mounted to a base frame. The conveyor belt mounting structure is mounted to the base frame for at least limited movement between first and second positions in a direction in which the conveyor belt moves over the front and rear conveyor rollers.
The invention also provides an x-ray technique-based nonintrusive inspection apparatus having a housing which is designed, for purposes of keeping contaminants from entering the housing, to have a higher pressure inside the housing than externally of the housing. The nonintrusive inspection apparatus includes a base frame, tunneling, an x-ray source, paneling, and a fan. The tunneling is mounted to the base frame and has a first end and a second end opposing the first end. The x-ray source which, when operated, creates radiation within the tunneling. The paneling is located around the tunneling and the x-ray source so that the paneling and the base frame jointly define a housing around the tunneling and the x-ray source. The housing has an entry aperture in proximity to the first end, and an exit aperture in proximity to the second end of the tunneling. The housing also has an air inlet opening. The fan is positioned to draw air through the inlet opening into the housing. The housing is formed, the entry aperture seals with the first end of the tunneling to an extent sufficient, and the exit aperture seals with the second end of the tunneling to an extent sufficient so that the confines of the housing are at a higher pressure than externally of the housing when the fan draws into the housing.
The invention also provides an x-ray technique-based nonintrusive inspection apparatus which may be cooled without necessarily having a fan mounted to a rotating gantry enclosure thereof. The nonintrusive inspection apparatus includes a support frame, a CT scanner subsystem, a plenum, an air-conditioning unit, and a duct. The CT scanner subsystem is rotatably mounted to the support frame and has a gantry enclosure. At least one air passage is formed into the gantry enclosure. The plenum is nonrotatably mounted to the support frame. The plenum is located externally of the gantry enclosure over the air passage so that the confines of the plenum are in communication with the air passage. The air-conditioning unit includes a fan. The duct connects the air-conditioning unit with the plenum. When the fan is operated, air passes from the air-conditioning unit through the duct to the plenum, from the plenum through the air passage into the gantry enclosure, and from the gantry enclosure through the radiator.